Update: Problem solved. My wife and I have identical S4's, which replaced our iphones!!( a definite upgrade). The problem, as she told me was that when a call came in and she answered it, her speaker was on. I finally got her phone and looked at it. When a call came in, she did not get the home screen with a greeen and red swipe options. She got a large, Answer or Reject screen. When you pressed Answer, the speaker indeed was on. I went through each of our settings under Call and Notifictions, etc and could not see any difference in our phones. I then went to the top pull down screen that has the wifi, GPS, etc. As I was going through them, I noticed that she must have accidentally turned on Drive Mode. When I turned it off, her phone returned to normal, with incoming calls going to the home screen with the green and red swipe options. I hadn't ever seen the Drive Mode screen, since I never use it. You learn something new every day!! Loving our S4's!!